/*
 * Copyright (C) 2013 The Guava Authors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.google.common.collect.testing.google;

import static com.google.common.collect.testing.Helpers.assertEmpty;
import static com.google.common.collect.testing.features.CollectionFeature.ALLOWS_NULL_QUERIES;
import static com.google.common.collect.testing.features.CollectionFeature.ALLOWS_NULL_VALUES;
import static com.google.common.collect.testing.features.CollectionFeature.SUPPORTS_REMOVE;
import static com.google.common.collect.testing.features.CollectionSize.SEVERAL;
import static com.google.common.collect.testing.features.CollectionSize.ZERO;

import com.google.common.annotations.GwtCompatible;
import com.google.common.annotations.GwtIncompatible;
import com.google.common.collect.testing.Helpers;
import com.google.common.collect.testing.WrongType;
import com.google.common.collect.testing.features.CollectionFeature;
import com.google.common.collect.testing.features.CollectionSize;

import java.lang.reflect.Method;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;

import org.junit.Ignore;

/**
 * Tests for {@code Multiset#remove}, {@code Multiset.removeAll}, and {@code Multiset.retainAll} not
 * already covered by the corresponding Collection testers.
 *
 * @author Jared Levy
 */
@GwtCompatible(emulated = true)
@Ignore // Affects only Android test runner, which respects JUnit 4 annotations on JUnit 3 tests.
public class MultisetRemoveTester<E> extends AbstractMultisetTester<E>
{
    @CollectionFeature.Require(SUPPORTS_REMOVE)
    public void testRemoveNegative()
    {
        try
        {
            getMultiset().remove(e0(), -1);
            fail("Expected IllegalArgumentException");
        }
        catch (IllegalArgumentException expected)
        {
        }
        expectUnchanged();
    }

    @CollectionFeature.Require(absent = SUPPORTS_REMOVE)
    public void testRemoveUnsupported()
    {
        try
        {
            getMultiset().remove(e0(), 2);
            fail("Expected UnsupportedOperationException");
        }
        catch (UnsupportedOperationException expected)
        {
        }
    }

    @CollectionFeature.Require(SUPPORTS_REMOVE)
    public void testRemoveZeroNoOp()
    {
        int originalCount = getMultiset().count(e0());
        assertEquals("old count", originalCount, getMultiset().remove(e0(), 0));
        expectUnchanged();
    }

    @CollectionSize.Require(absent = ZERO)
    @CollectionFeature.Require(SUPPORTS_REMOVE)
    public void testRemove_occurrences_present()
    {
        assertEquals(
                "multiset.remove(present, 2) didn't return the old count",
                1,
                getMultiset().remove(e0(), 2));
        assertFalse(
                "multiset contains present after multiset.remove(present, 2)",
                getMultiset().contains(e0()));
        assertEquals(0, getMultiset().count(e0()));
    }

    @CollectionSize.Require(SEVERAL)
    @CollectionFeature.Require(SUPPORTS_REMOVE)
    public void testRemove_some_occurrences_present()
    {
        initThreeCopies();
        assertEquals(
                "multiset.remove(present, 2) didn't return the old count",
                3,
                getMultiset().remove(e0(), 2));
        assertTrue(
                "multiset contains present after multiset.remove(present, 2)",
                getMultiset().contains(e0()));
        assertEquals(1, getMultiset().count(e0()));
    }

    @CollectionFeature.Require(SUPPORTS_REMOVE)
    public void testRemove_occurrences_absent()
    {
        int distinct = getMultiset().elementSet().size();
        assertEquals("multiset.remove(absent, 0) didn't return 0", 0, getMultiset().remove(e3(), 2));
        assertEquals(distinct, getMultiset().elementSet().size());
    }

    @CollectionFeature.Require(absent = SUPPORTS_REMOVE)
    public void testRemove_occurrences_unsupported_absent()
    {
        // notice: we don't care whether it succeeds, or fails with UOE
        try
        {
            assertEquals(
                    "multiset.remove(absent, 2) didn't return 0 or throw an exception",
                    0,
                    getMultiset().remove(e3(), 2));
        }
        catch (UnsupportedOperationException ok)
        {
        }
    }

    @CollectionFeature.Require(SUPPORTS_REMOVE)
    public void testRemove_occurrences_0()
    {
        int oldCount = getMultiset().count(e0());
        assertEquals(
                "multiset.remove(E, 0) didn't return the old count",
                oldCount,
                getMultiset().remove(e0(), 0));
    }

    @CollectionFeature.Require(SUPPORTS_REMOVE)
    public void testRemove_occurrences_negative()
    {
        try
        {
            getMultiset().remove(e0(), -1);
            fail("multiset.remove(E, -1) didn't throw an exception");
        }
        catch (IllegalArgumentException required)
        {
        }
    }

    @CollectionFeature.Require(SUPPORTS_REMOVE)
    public void testRemove_occurrences_wrongType()
    {
        assertEquals(
                "multiset.remove(wrongType, 1) didn't return 0",
                0,
                getMultiset().remove(WrongType.VALUE, 1));
    }

    @CollectionSize.Require(absent = ZERO)
    @CollectionFeature.Require({SUPPORTS_REMOVE, ALLOWS_NULL_VALUES})
    public void testRemove_nullPresent()
    {
        initCollectionWithNullElement();
        assertEquals(1, getMultiset().remove(null, 2));
        assertFalse(
                "multiset contains present after multiset.remove(present, 2)",
                getMultiset().contains(null));
        assertEquals(0, getMultiset().count(null));
    }

    @CollectionFeature.Require({SUPPORTS_REMOVE, ALLOWS_NULL_QUERIES})
    public void testRemove_nullAbsent()
    {
        assertEquals(0, getMultiset().remove(null, 2));
    }

    @CollectionFeature.Require(value = SUPPORTS_REMOVE, absent = ALLOWS_NULL_QUERIES)
    public void testRemove_nullForbidden()
    {
        try
        {
            getMultiset().remove(null, 2);
            fail("Expected NullPointerException");
        }
        catch (NullPointerException expected)
        {
        }
    }

    @CollectionSize.Require(SEVERAL)
    @CollectionFeature.Require(SUPPORTS_REMOVE)
    public void testRemoveAllIgnoresCount()
    {
        initThreeCopies();
        assertTrue(getMultiset().removeAll(Collections.singleton(e0())));
        assertEmpty(getMultiset());
    }

    @CollectionSize.Require(SEVERAL)
    @CollectionFeature.Require(SUPPORTS_REMOVE)
    public void testRetainAllIgnoresCount()
    {
        initThreeCopies();
        List<E> contents = Helpers.copyToList(getMultiset());
        assertFalse(getMultiset().retainAll(Collections.singleton(e0())));
        expectContents(contents);
    }

    /**
     * Returns {@link Method} instances for the remove tests that assume multisets support duplicates
     * so that the test of {@code Multisets.forSet()} can suppress them.
     */
    @GwtIncompatible // reflection
    public static List<Method> getRemoveDuplicateInitializingMethods()
    {
        return Arrays.asList(
                Helpers.getMethod(MultisetRemoveTester.class, "testRemove_some_occurrences_present"));
    }
}
